Twitter's active users grow 900% in one year

Twitter is growing at a phenomenal rate, according to an employee post on the Twitter blog.

Just how phenomenal? Try this: Active users have increased 900% in a year, and two times the traffic that Twitter's website receives heads to Twitter's APIs -- meaning that far more people use outside clients to manage their tweeting, including SMS.

Not bad for a company of just 29 employees.

MORE NEWS: Last night, Twitter closed on funding with Peter Fenton from Benchmark and Todd Chaffee from Institutional Venture Partners. Fenton will be joining Twitter's board of directors, too:

We are now positioned extremely well to support the accelerating growth of our service, further enable the robust ecosystem sprouting up around Twitter, and yes, to begin building revenue-generating products. Throughout this year and beyond, our small team will grow much bigger to meet the challenges and opportunities ahead.

Twitter is making a real impact around the world as people, companies, and organizations everywhere discover a powerful new way to communicate and find out what's happening—right now. With these new partnerships and this new funding, we are in a position to move more confidently toward our vision for a robust and successful Twitter, Inc.

Not bad at all.

Even more interesting is The Pew Internet and American Life Project's study of Twitter usage (officially, "Twitter and status updating"). It found that -- deep breath here -- American Twitter users are predominately young, poor, blog-centric, social-network-happy urbanites who like to read the news on their mobile devices.

As if you didn't already know!

Some fast facts:

The average Tweeter is 31. (By comparison, MySpace has an average age of 27; Facebook is 26; LinkedIn is in the 40s)
In the Twitterverse, 25- to 34-year-olds hold a slight population majority over 19- to 24-year-olds by about 1 percent.
17 percent of adult Internet users who make $30,000 or less also tweet, while only 10 percent of households making $75,000 or more broadcast their status into cyberspace. This generally matches the age demographic, since young people make less than their elders.
Tweeters are also more ethnically diverse and more likely to live in a city. This also matches the age demographics.
Twitter users use their status updates as one piece of a much larger social media landscape.
Finally, Twitter users are more likely to consume and read blogs than other Internet users: Fifty-seven percent of tweeters have read a blog, and 21 percent said yes when asked if they read a blog yesterday. By comparison, only 9 percent of non-tweeters said they read a blog yesterday and only 29 percent have ever read a blog. The statistic gets even wider when talking about blog creators: 29 percent of tweeters have created a blog, while only 11 percent of the Twitterless have ventured into the world of Wordpress and Moveable Type.

If only users knew Twitter is a microblogging service.

More on ZDNet about Twitter: